Boiler tube



June 29 1926.

J. A. DOBLE BOILER TUBE Filed Sept. 15,1919

INVENTOR. Jar/1v :DOBLE wwjnf A TTORNEYS.

Patented June 29, 1926.

UNITED STATES PATENT OF JOHN A. DOBLE, OF SAN FRANCISCO, CALIFORNIA.

BOILER TUBE.

Application filed. September The invention relates to boiler tubes, and particularly to water tubes foruse in small highpowered boilers for use in vehicles and in other installations. In boilers of this character a heavy steam demand on the boiler frequently produces undesirable discharge of water with the steam and frequently greatly reduces the boiler pressure on account of the inability of the boiler to produce steam in sufficient quantity to meet the demand.

It is therefore an object of this invention to provide a boiler which is constructed to obviate the discharge of water with the steam, regardless of the steam demand 0 the boiler.

Another object of the invention is to increase the steaming capacity of the boiler by increasing the surface of water exposed to the heat.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description, where I shall outline in full, that form of the invention which I have selected for illustration in the draw ings accompanying and forming part of the present specification. In said drawings I have shown one form of the device of my invention, but it is to be understood that it is not limited to such form, since the invention, as expressed in the claims, may be embodied in a plurality of forms.

Referring to said drawings:

Figure 1 is a longitudinal section of a boiler tube equipped with one form of device of my invention.

Figure 2 is a cross section, on a larger scale, of the tube taken on the line 2-2, Figure 1.

Figure 3 is a cross section, on a larger scale, of the tube, taken on the line 33, Figure 1.

My invention is particularly adapted, although not restricted, to use in connection with water tube boilers, which are subjected to great and frequent variations in steam demand, such as is encountered in automo= bile, truck, tractor and aviation uses. The invention is further particularly adapted for use in small boilers which must necessarily be employed in such uses. In accordance with my invention, I provide means within the tube, whereby the flow of steam through the tube causes a rotary motion to be imparted to the water in the tube, separating it 15, 1919. Serial No. 323,802.

from the steam by centrifugal force, and

over the inner surface of the tube, thereby increasing the area of contact between the water and the tube and increasing the steam-liberating surface of the water. 7

In the drawings I have shown one tube of a series tube boiler, equipped with the means of my invention, but it is to be under-- stood that the invention is in no manner limited to the particular boiler tube shown. Arranged in the tube are one or more devices, depending upon the length of. the tube and other characteristics of the boiler, for imparting rotary motion to the water. In the particular tube shown, four such devices are shown, but any number may be used. The ends of the tubes have been constricted after the insertion of the device, to meet the requirements of a particular type of 1boiler, but such constriction is not essentia I Disposed in the tube and spaced apart longitudinally therein, are one or more shells .2 through which the steam and water pass successively. Each shell comprisesa flanged annular portion provided with a spiral extension or vane. The annular portion or apertured wall 3 carries flanges i and 5 at its outer and inner peripheries respectively. The outer flange 4 engages the inner surface of the tube 6 while the inner flange 5 surrounds an aperture 7, through which the steam passes. Springing from the rear face of the annular portion is a spiral or involute vane 8, into the center of which the aperture 7 opens. The axis of the vane 8 is preferably concentric with or parallel to the axis of the tube 6 and the discharge aperture of the spiral is located on the lower side of the vane 8. The end of the spiral vane is closed by the cap 9, having an aperture therethrough and being provided on its rear side with an annular shoulder 12. Engaging the shoulder 12 and bearing against the cap 9 is a tube or conduit 14, provided with apertures 15 along its upper surface. This tube, at its other or discharge end, engages the flange or shoulder 5 on the next shell 2, which is of the same construction as the first shell 2. A sufficient number of shells and apertured tubes are arranged successively within the boiler tube and these are held rigidly together by a rod 16 extending iongitudinally through them and the yoke or spider 17 which engages the annular portion 3 of the first shell 2. The assembled device, consisting of one or more units, is held in the boiler tube in any suitable manner, such as by the creases or indentations 18 formed in the boiler tube at opposite ends of the outer flange 4. V

In operation, the tube is filled With Water and steam, and when there is no steam demand on the boiler, the Water lies in the bottom portion of the tube 6; When a steam demand is made ontheboiler, the steam flows through the apertures 7 and through thespiral vane and is discharged more or less tangentially into the Water lying in the tube. This produces a rapid rotary motion of the Water and steam around the inner surface of the tube bringing the Water into contact with the entire inner surface of the tribe and separating a large portion of it from the steam. The steam and remaining Water pass through the apertures 15' into the tube 14 and progress through the successive rotary motion producing shells in each of which more Water is separated and evaporated so that finally no more Water, remains in the steam. The: flow of the steam is retarded very little and on large steam demands practically not at all. In a series tube boiler each successive tube contains a smaller proportion of Water and the amount of Water in the last tube, or the tube adjacent the outlet, is'such that regardless of the steam demand, no Water is carried over. Sufficient Water flows'with the steam from one steam tube to another, to insure the proper amount of Water in each tube.

I claim:

1. The combination With a boiler tube adapted to contain steam and Water, of a Wall disposed Within said tube and provided With a central aperture through Which steam and Water pass, and a spiral vane arranged behind said Wall and receiving steam and Water thru said aperture and discharging them tangentially in the tube.

3. The combination With a boiler tube of a plurality of shells spaced apart longitudinally in said tube, each shell comprisin a wall having an aperture through Whicfi Water and steam are adapted to pass and having means for discharging Water and steam tangentially in said tube, and apertured conduits interposed between the successive shells.

4. The combination with a boiler tube of a plurality of shell spaced apart longitudinally in said tube, spiral vanes on said shells, apertured conduits interposed between the vane on one shell and the adjacent shell, and means for holding said shells and conduit together.

In testimony whereof, I have hereunto set my hand at San Franc1sco, California, this 30th day of August, 1919.

JOHN A. DOBLE. 

